- Coalsack
-
/kohl"sak'/, n. Astron.a dark nebula in the southern constellation Crux, whose dust particles obscure light from Milky Way stars behind it. Also, Coal Sack. Also called Southern Coalsack.[1625-35; COAL + SACK1]
* * *
Dark nebula in the Crux constellation (Southern Cross).It reduces the brightness of stars beyond it by 1–1.5 magnitudes. Easily visible against a starry background, it is probably about 550–600 light-years from Earth and 20–30 light-years in diameter. It figures in legends of peoples of the Southern Hemisphere and has been known to Europeans since с 1500. The Northern Coalsack, in the constellation Cygnus, is similar in nature and appearance but somewhat less obvious.* * *
▪ nebulaa dark nebula in the Crux constellation (Southern Cross). Easily visible against a starry background, it is perhaps the most conspicuous dark nebula. Starlight coming to Earth through it is reduced by 1 to 1.5 magnitudes. The Coalsack is about 500 light-years from Earth and 50 light-years in diameter. It figures in legends of peoples of the Southern Hemisphere and has been known to Europeans since about 1500. The Northern Coalsack, in the constellation Cygnus, is similar in nature and appearance but somewhat less prominent.* * *
Universalium. 2010.